Main.c

Arduino

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <MsTimer2.h>
#include <LedControl.h>

int count = 0;
int DIN = 12;
int CS =  11;
int CLK = 10;
const float circle = 1.89; // 周长
unsigned int timeCount = 0;


byte L0[8] = {0x60,0x90,0x90,0x90,0x90,0x90,0x60,0x00};
byte L1[8] = {0x20,0x60,0xa0,0x20,0x20,0x20,0xf0,0x00};
byte L2[8] = {0x60,0x90,0x10,0x20,0x40,0x80,0xf0,0x00};
byte L3[8] = {0x60,0x90,0x10,0x20,0x10,0x90,0x60,0x00};
byte L4[8] = {0x20,0x60,0xa0,0xf0,0x20,0x20,0x20,0x00};
byte L5[8] = {0xf0,0x80,0x80,0xe0,0x10,0x10,0xe0,0x00};
byte L6[8] = {0x20,0x40,0x80,0xe0,0x90,0x90,0x60,0x00};
byte L7[8] = {0xf0,0x90,0x10,0x20,0x40,0x40,0x40,0x00};
byte L8[8] = {0x60,0x90,0x90,0x60,0x90,0x90,0x60,0x00};
byte L9[8] = {0x60,0x90,0x90,0x70,0x20,0x40,0x80,0x00};

byte R0[8] = {0x06,0x09,0x09,0x09,0x09,0x09,0x06,0x00};
byte R1[8] = {0x02,0x06,0x0a,0x02,0x02,0x02,0x0f,0x00};
byte R2[8] = {0x06,0x09,0x01,0x02,0x04,0x08,0x0f,0x00};
byte R3[8] = {0x06,0x09,0x01,0x02,0x01,0x09,0x06,0x00};
byte R4[8] = {0x02,0x06,0x0a,0x0f,0x02,0x02,0x02,0x00};
byte R5[8] = {0x0f,0x08,0x08,0x0e,0x01,0x01,0x0e,0x00};
byte R6[8] = {0x02,0x04,0x08,0x0e,0x09,0x09,0x06,0x00};
byte R7[8] = {0x0f,0x09,0x01,0x02,0x04,0x04,0x04,0x00};
byte R8[8] = {0x06,0x09,0x09,0x06,0x09,0x09,0x06,0x00};
byte R9[8] = {0x06,0x09,0x09,0x07,0x02,0x04,0x08,0x00};

byte STOP[8] = {0x18,0x3c,0x3c,0x18,0x18,0x00,0x18,0x18}; //  输出感叹号“！”

LedControl lc=LedControl(DIN,CLK,CS,4);

void setup() {
    attachInterrupt(0, blink, LOW);
    Serial.begin(9600);  // 串口通信波特率
    lc.shutdown(0,false);       //启动时，MAX7219处于省电模式
    lc.setIntensity(0,3);       //将亮度设置为最大值
    lc.clearDisplay(0);         //清除显示
    MsTimer2::set(1, timeTo);  // 设定时间间隔
    MsTimer2::start();  // 启动定时器
}

void loop() {
}

void timeTo() {
    // 计时
    timeCount += 1;
    if (timeCount > 4000) {
        printMerge(L0,R0);
    }
}

void blink() {
    // 阈值判断
    if (timeCount > 100){
        calSpeed();
    }
    timeCount = 0;
}

// 计算速度
void calSpeed() {
    float speed = circle / timeCount * 3600 + 1;  // 3600为1000ms*3.6km/h, +1 为延迟补偿
    if (speed > 50.0) {
       printByte(STOP);
    } else {
        // 显示换算
        int L_tmp = speed / 10;
        int R_tmp = int(fmod(speed, 10));   // 浮点数取余
        byte L[8];
        byte R[8];
        switch (L_tmp) {
            case 0: memcpy(L, L0, 8); break;
            case 1: memcpy(L, L1, 8); break;
            case 2: memcpy(L, L2, 8); break;
            case 3: memcpy(L, L3, 8); break;
            case 4: memcpy(L, L4, 8); break;
            case 5: memcpy(L, L5, 8); break;
            case 6: memcpy(L, L6, 8); break;
            case 7: memcpy(L, L7, 8); break;
            case 8: memcpy(L, L8, 8); break;
            case 9: memcpy(L, L9, 8); break;
        }
        switch (R_tmp) {
            case 0: memcpy(R, R0, 8); break;
            case 1: memcpy(R, R1, 8); break;
            case 2: memcpy(R, R2, 8); break;
            case 3: memcpy(R, R3, 8); break;
            case 4: memcpy(R, R4, 8); break;
            case 5: memcpy(R, R5, 8); break;
            case 6: memcpy(R, R6, 8); break;
            case 7: memcpy(R, R7, 8); break;
            case 8: memcpy(R, R8, 8); break;
            case 9: memcpy(R, R9, 8); break;
        }
        printMerge(L, R);
    }    
}

// 单字符输出
void printByte(byte character []) {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0, i, character[i]);
  }
}

// 双字符输出
void printMerge(byte x [], byte y []) {
    byte c[8];
    for (int i = 0; i < 8; i++) {
        c[i] = x[i] + y[i];
    }
    printByte(c);
}

// 自行车车轮周长3.14 * 600 =1890mm